Sensors constitute a connection between the physical medium and industrial electrical/electronic devices. These devices are used in many industrial processes such as control, security, and monitoring.
Today, it is possible to mention hundreds of sensor types manufactured. Sensors can be categorized according to many different criteria such as the magnitude measured, output power, power requirements, etc.
Active sensors require an external energy supply. They generally operate on a battery or an accumulator. However, the main problem of sensor networks is energy constraint.
In the state of the art on this technique, the invention mentioned in the U.S. Pat. No. 7,835,226 B2, it is proposed to perform communication and powering in wireless sensor networks through a pipe.
Another patent document in the state of the art is WO 2008/058076 A1. The invention presented in this document is about supplying energy to the underground sensors used in petroleum and gas extraction, and about wireless communication.